The only mystery left in the Republican presidential race is guessing the moment when Rick Santorum bows to the inevitable. It may come with a gesture of face-saving capitulation before his home-state primary on April 24, with a feeling of forgotten-man frustration as Mitt Romney nears a delegate majority in early June, or with a final burst of angry defiance on the eve of the Tampa Convention. But whenever he bowls his last game on the campaign trail and fends off the last question about his illusory path to victory, I hope it will be remembered what Santorum single-handedly accomplished during sweater-vest season.

More than any presidential candidate since maybe Gary Hart in 1984, Santorum vindicated the quixotic dreamers who struggle on despite invisible poll ratings, tin-cup financing, and the dismissive wisecracks from political insiders. Santorum was a throw-back candidate—not only with his 1950s social values, but also in his forged-by-necessity embrace of the most old-fashioned way of running for president. In Iowa, where he made his move in the polls only two weeks before the January 3 caucuses, Santorum campaigned everywhere, responded at (sometimes tedious) length to every voter question, and cheerfully deflected skeptical press queries like the one I posed to him in mid-December: “Some days, don’t you get discouraged?”

What is already partially lost in the press coverage is how close Santorum came to stopping Romney—or, at least, sending the GOP race into overtime.